Loop-antenna unit



Aug. '7.,l 1945. M. BRowNsHlELD l2,381,334

LOOP ANTENNA UNIT Filed sept.v e, 1944 2 sheets-sheet 1 man :if: nu lj in umm u Aug. 7, 1945. M. L. BRowNsHlELD 2,381,334

LOOP 4ANTENNA UNIT A Filed sept. e, 1944 A 2 sheets-sheet 2 frm*- fr,

1..... m. ff.; 'l

Patented Aug. 7, 1945 UNITED. smiliesI Pare-N frN oFFIc-:E

A L t i 2,381,334-

L 0I.A ANTENNA UNIT e t Milton L.' Brownshield, Dobbs Ferry, N. Y..

Application September' 6, 1944; SerialLNo. 552,829

(Cl. Z50-11') Claims.

Theiepres'ent"invention ".relates primarily to= antenna loop units and the associatedistructure It is among 'theobjectswofe the Iinvention. to

- 'provide a Isimplel and rugged construction of the has."aamouni'iilngI plug@ unitary therewith carrying!montants'liconrliectedI to .=the'. terminals.:l of 3 the;M antennarcoilnthat.encircles aloopfcarryingLframe:

rigidlyliVv aiixedrwiithini thewcasingi-f Preferably;-

, the torus casing has a tube'extending:-diametricallyifhtl'ierethroughl for mounting .a.conductor theret'nnt@@theiuppernend -1of.whichiisr :to 1(be: at-r tached to the sense or. Aavhip santerma:to-be cony nectednto .thereceiversY by.` :wayy `of..1a..central vcontact-,cin .thef..-plugf.-:. rPreferably.'the-llengths ofA the4 tubeiiwithiniz-.thetorusrcasingff'are .enclosed ina plasticsleeve bonded'. tOiisadccasing aat .the Var# ilousiholves: infthe datter... through which. the L'tube.

extends, athereby.ftoz.,render tthe #structure water 'pranoaY .Inzithel' accompanying.. drawings.. in .which'- isshownxfonerof A.various-possible..embodiments of thefseveralfeaturesofA the invention',

Fig. 1 is a side elevation of the.loop;lantenna unit :shown in .xplaceifonctheetopi of. a Ireceiver carrying Athe same,

Elgar@ is-,ta view.` in'` .longitudinal across-section.. o;..the fassemblypshownl in-Fig1a 1 and :oILaJgreatly y enlarged.scale;;with-.parts brokenv away,

Fig. 3 is a transverse sectional view takenion...

therefor:

sion has a unitary interior ledge,V said ledges in the assembled structure formingan annular rib AISI which is lodged in a Vperipheral groove 2Il'` about the correspondingly reducedend 2I` of-a4 plug P which is embraced by the' neck The rim of-the neck abuts the shoulders 22`f'on the: plug,.the lower part of which isof the'sameV diameter as and flush with neck N. Preferably theneck N of the torus casing has aixed there in radial threaded metal bushings-123 for ac-v commodating screws 241to aix'to the torus -casinga metal .mounting-shelll25f Theshell 25 has a peripheral. shoulder 25 with a-positioning lug 2l. The torus casing vis of plastic, preferably ofy polystyrene andA its elementsl are welded or bonded together by means of polystyrene cement so as to afford a thoroughly waterproof construction. The loop coil frame F and the plugP may be similarly cemented in place inthe Vtorus A casing.

Referring .now to the: drawings;;,the antenna..V

unit-.of f .theinvention i compriseswa `torus casing.v

C. desirably of polystyrene, for. enclosing/the direction iinding` antenna loops Preferablyyrthe and- II wln'ch, are interkeyed by DIOVidingzpe-- riphel grooves IIi.,mid-wayA between the .abuttinglpairs of edgcaffor accommodatingnthelateral-i .edges of a generally cy 'ndricalp loop. coil frame. :Fgv which" tliisaeiten sgacroissythe -.torus-.. casing,n substane v casing 1.C srmadefup-of two annular troughsul The plug .P vmounts the contacts for the anV`yr riveted thereto as at 33 and embedded in'y the plug', to the inner upwardly protruding end of which is connected at 34 the corresponding. extremity of the antenna loop I '1.

'I'he torus casing is metal plated, desirably silver plated at 35, for grounding connection and said plating is interrupted as at 36- and 3l vfor access of the radio impulses to the antenna coil Il within the casing.

In a preferred embodiment,r the positiondinding coil antenna which is of courseto be connected to a tuning eye circuit (not shown) in the receiving unit R, has associated therewith a sense antenna which is to be connected toa conventional radio receiver (not shown) which is part of the unit R. The sense antenna is arranged to be mounted immediately above as an extension of the vertical diameter of theA torus casing, as

indicated at S; In a preferred construction. best shown in Fig. 2,` a metal tubey 40 `extends through the thickness'of the plug P diametrially through the hollow torus casing C-i. e. -throughv the lower part of thefinner wallthereof atih`ole:4'l ,fU

Each` cylindrical contact has a connector strip-32' the upper part of said inner wall at hole 42 and the thickened upper end 43 of the vouter wall at hole 44. The loop coil frame F is also perforated at 45 and 46 to afford passage for tube 40, the coil l1 being wound as shown in Fig. 4 to straddle said tube. Encompassing the mid-section of tube 40 is a metal tube 41, which is Swaged at its ends to engage the torus casing. In this embodiment, the metal plate 35 is applied after assembly of the diametral member, so that the plating extends over metal tube 41 as well as its swaged ends. Sealing tubes 19 and 80 of polystyrene respectively enclose the lower and upper parts of metal tube 40 and are secured in place at said openings 4I, 42 and 44 by means of polystyrene cement, so as to afford thoroughly secured water-tight closure for the apertures in the casing C. The metal tube 40 is secured in position by a nut 48 threaded about the lower end thereof and abutting against the plug P. 'Ihe upper end of the metal tube has threaded thereon the nut 49 which abuts the iiat surface 50 on .the torus casing. That nut is securely affixed by means of a radial pin l. A connecting wire 52 soldered at its lower end 53 to a terminal prong 54 retained in an insulating bushing 55l in the lower end of tube 49, extends axially through the length of said tube, and at its upper end through the axial aperture 56 of a mounting nipple 51 resting upon insulating washer 8l and to the upper end of which said wire is soldered at 58. A pin 59 rising from the headof nipple 51 extends into a connector cap 60 threaded upon the nut 49 and keeping the parts in assembled relation. A

locking screw 6I radially through said cap extends into nut 49 and afxes the cap against rotation. The nipple 51 as above indicated, serves as the mount for the removable sense or whip antenna S. A series of frusto-conical insulators 62 encompass wire 52 and thereby effectively insulate it from the inner wall of the metal tube 48. The parts thus far described constitute the loopantenna unit as an article of manufacture.

It will be understood that a set of the loop antenna units described would be available, each with a loop antenna of characteristic number of turns for use each for a particular band of wave lengths. The loop antenna units are identical in size and shape and may be distinguished by numeral, letter or color mark.

The receiver unit R as above suggested, may be conventional, and encloses the tuning eye and its circuit (not shown) as well as the radio receiver (not shown). The tuning eyecircuit is connected by screws 65 to spring terminals 66 and 61, each extending in arcuate relation upon an insulating platform 68 on the instrument. The arcuate terminals are bowed for resilient contact respectively with the inner contact ring 30 and the outer contact ring 3|. In order to keep the spring pressure balanced, the terminal 66 is preferably paired by diametrically opposite terminal 66 and terminal 61 by a diametrically opposed terminal 61'. The nut 48 and terminal prong 54 of the whip antenna extend into the socket end 69 of a central grounding terminal cup 1U aiiixed by nut 1I to the platform 68 for connection to the receiving set. To this end, the prong 54 extends into a corresponding metal shell 82 affixed at its rim to the lower face of an insulating washer 83 resting in cap 1l,wire 84 soldered to shell 82 eilecting connection to the radio receiver (notl shown).

A edge contact into a unitary water-tight torus The mounting shell 25 of the Vloop antenna unit, ts slidably into a collar 15 that rests at flange 15' upon azimuth ring 16. Upon the rim of collar 15 rests the rib 26, the lug 21 of which is keyed into a corresponding notch 11 in said rim, for correct location with respect to the scale. A cap nut 18 screwed upon the threaded exterior of collar 15 maintains the parts assembled.

The utility of the unit for locating a, broadcasting Station is obvious. The torus casing together with the azimuth ring 16 is turned until the tuning eye indicates the direction of the sending station, whereupon the sense or whip antenna S if used, will give the volume of the impulse. Since the whip or sense antenna is coaxial with the axis of adjustment of the loop antenna, the errors incurred where the two antenna are spaced laterally by as little as a foot are manifestly obviated. Accordingly the unit is of particular utility for rapidly locating a transmitter.

Manifestly the loop antenna unit could be used in association with any receiving unit.

The antenna unit is especially easy to apply. It is strong, rugged and waterproof, so that it is not subject to the disturbances of short-circuit due to the admission of water. It could be jettisoned and submerged in the ocean and recovered intact.

As many changes could be made in the above apparatus, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A loop antenna unit,`comprising a pair of complementary annular insulating troughs, each with a short radial neck trough extension, a generally cylindrical loop support frame, an antenna loop thereabout, a contact carrying plug, and means bonding the annular troughs in edge to casing that has a neck extension, with the loop support frame and the plug rigidly clamped respectively in the torus casing and in the neck extension thereof.

2. The combination recited in claim l in which the contacts in the plug are coaxial cylinders exposed at the lower end of the plug, each having a connector protruding from the upper end of the plug to which the ends of the antenna loop are connected.

3. A loop antenna unit, comprising a pair of complementary annular insulating troughs, each with a short radial neck trough extension, said troughs being adapted to register in edge to edge relation to form a torus casing with a lateral neck extension, a cylindrical loop support frame, an antenna loop thereabout, said frame extending transversely across said registering edges and having lateral edges keyed in corresponding grooves in the troughs, a terminal plug encompassed by said neck and peripherally keyed there- 1n, means bonding the troughs into a unitary water-tight torus casing, with the loop coil frame andthe plug rigidly retained in place, said plug having a pair of exposed terminal rings concentric therewith, and terminals through said plug from the respective rings to the antenna loop.

' the torus casing is metal plated at its exterior with narrow gaps in the plating.

5. A loop antenna unit comprising an insulating torus casing having a mounting plug, a generally cylindrical loop coil frame enclosed in said casing with an antenna loop thereabout, current y leads from said coil extending into said plug, coaxial contact rings carried byl said plug and connected to said leads, said torus casing having a tube extending across the entire outer diameter I thereof, a wire through said tube insulated therefrom, having a mount at its upper end for a sense l antenna and having a terminal at its lower end,

the torus casing and the associated tube for the vsense antenna forming an integral water-tight structure.

about said wire spacing the same from the metal tube, a sense antenna mount aflixed upon the f 6. A loop antenna unit, comprising amounting plug having a pair of coaxial cylindrical contacts and a central contact, all exposed at the lower 'end thereof, an upright insulating torus casing unitary with said plug having a cylindrical insulating loop mounting frame therein with an antenna loop coiled lthereabout,"the latter being connected at its ends to the cylindrical contacts, an upright insulating tube extending through said )plug and diametrally through said torus casing and bonded with respect to the latter in a watertight structure, a wire connected to said central terminal and extending axially through said tube, a metal tube lining said insulating tube and about said wire, insulators encompassing said wire and shielding the same lfrom said metal tube and a mount at the upper part of said torus casing for aflixing a sense antenna to the upper end of said wire f 7. A loop antenna unit, comprising an insulat- K 'ing plug, a pair of coaxial cylindrical contacts afllxed therein and protruding from the lower end thereof, connectors within said plug joined to said annular contacts and protruding from the upper end Aof said plug, a torus casing of plastic,

y. keyed' with respect to said plug, a generally cylindrical loop support frame affixed in the ininterior of said torus casing, substantially midway between the inner and outer diameter thereof, anfantenna coil about said frame having its ends joined to said connectors, a metal tube extending through the height of said plug and diametrally of said torus casing through the upper end thereof,fplastic tube lengths about said metal tube and within said torus casing and contacting and bonded to the corresponding walls of the torus casing and forming a water-tight seal with respect thereto, a wire axially through said metal l tube affixed at the lower end thereof, insulators upper part of said torus casing andaligned with said tube, said axial wire being anixedlto said mount. .V

8. The combination recited in claim 'l in which the plug is reduced in diameter at its upper end, the torus casing is made of two coacting annular troughs, each having a short radial neck trough keyed to the corresponding part of the plug and an external conformation flush with the cylindrical surface of the plug below the reduced portion and each'having a metal bushing radially embedded therein for purposes of afxing the same.

9. A loop antenna unit, comprising an insulating torus casing having a direction nder coil encased therein, said casing having a terminal carrying appurtenance unitary therewith, a metal tube extending diametrally through said torus casing, insulating tube lengths thereabout within the torus casing and bonded thereto in watertight relation, a wire extending axially through said metal tube, means insulating said wire from said tube, a nut aflixing said tube at the lower end thereof to serve for grounding connection, a prong aixed to said wire at its lower end and insulated from said nut for connectionto a receiver, and sense antenna mounting means at the outer end of said wire.

10. A loop antenna unit, comprising an insulating torus casing for a direction finder coil encased therein, said casing having a terminal carrying mounting appurtenance unitary therewith, said appurtenance including ring terminals said casing for water-tight connection, a metal tube encompassing the median exposed length of metal tube and swaged at its ends against the wall of the torus casing and a metal coating plated upon said torus casing and said outer metal shell, said coating having limited areas of interruption for access of radio impulse to the finder coil.

MILTON L. BROWNSHIELD. 

